This was my first attempt to change fork oil on my own and it seemed to go very well and the biggest advantage was saving money from having a local shop do it for me. Iím somewhat mechanically inclined and decided to give it a try. I bought a RaceTech fork compressor tool for $136 shipped on eBay. If you do not have one of these tools, youíll need one, or use a homemade fork spring compression tool. (Iíve heard some folks can use c-clamps and ratchet style tie downs to compress fork springs).

I wonít get into the details on how to remove the forks from the bike. If you do not know how to do that, stop right now and donít attempt this on your own. Youíll want to note your suspension settings and the height the fork extends from the top clamp. Turn the rebound to #1 on the top of the fork. Most importantly, youíll also need to loosen the top cap of both forks prior to loosening the pinch bolts on the triple tree. Otherwise, you probably wonít be able to loosen the top cap if you remove the fork from the bike first. Donít completely remove the cap, or youíll be dealing with fork oil going everywhere when you slide the fork out of the triple tree. I just turned the cap 2 or 3 revolutions to get it started then loosened the pinch bolts and removed the fork from the triple tree.

Once youíve got the fork removed from the bike, you can completely unscrew the top nut then slide the upper tube down on the lower tube to see the internals. At this point, you have the option of draining the fluid out prior to compressing the spring, or you can drain the fluid later. I chose to leave the fluid in so I could take a measurement of how much fluid was in the fork prior to draining it just for my own curiosity.

With that said, I put the fork in the compressor tool and cranked it down to expose the locknut for the top cap.

Loosen the lock nut and then unscrew the top nut to remove if from the damper inside the fork. I removed the plastic spacer, metal washer, and spring then took a measurement of the current fork oil using small tape measure with mm on it.

I then drained the fluid out by turning the fork upside down. There is another metal washer thatíll come out of the fork too which is positioned just below the spring. I laid out the internals in order.

Once drained, remove axle pinch bolts to access the bolt from the bottom of the fork that holds the damper inside the fork. Loosen it all the way and remove the damper.

Pump the damper several times to remove all the oil inside of it. See how dark the old oil is in the cup?

Here are all the internals:

Now itís time to reinstall the parts, starting with the damper. Make sure the end of the damper lines up correctly inside the fork leg so itís properly seated.

Reinstall the bolt in the bottom of the fork to secure the damper (30Nm). Again, make sure the damper was lined up correctly to properly seat in the bottom of the fork leg. Now itís time to fill with fork oil. I went with Silkolene Racing SAE 10. OEM is SAE 7.5 and Dave Moss recommends SAE 15. If I feel #10 is still too light, Iíll go with #15 when I change the fluid again. The quantity to fill is 602ml. Since I donít have precise measuring cups, I filled an empty fork oil bottle to about 600 ml and slowly poured it into the fork tube.

You now have to pump the damping rod several times to get the fluid inside the rod. Again, not having the proper tool to thread on top of the rod, I simply used needle nose pliers and gently gripped the top of the damper rod and pulled it up and down several times. I then let the oil settle for about 15 minutes before I took my first measurement. Using my high tech tape measure, I took a few measurements and found the oil level just a few mm low from recommended air space (90mm). I poured a little more oil in to get it set right at 90mm from the surface of the oil to the top of the lower fork leg (not the top of the upper fork leg!). I forgot to take a photo showing the correct level. Sorry!

Now itís time to put the rest of the internals back in. Start with the metal washer that goes below the spring, then the spring itself, then the washer on top of the spring, then the plastic spacer. Put the fork back in the spring compression tool and crank down on the spring until the damping rod and lock nut will extend out of the plastic spacer. I used needle nose pliers to gently pull up the damper rod to thread the top nut on the rod. Be careful not to mess up the threads on the damper rod!

Screw the top nut down until it tightens slightly from ďbottomĒ out on the damper (not on the lock nut!). You may need to use a flat head screw driver (or some other flat tool like the wire cutters you see in the photos) wedged under the lock nut to keep it above the plastic spacer.

Now you need to check the number of clicks for the rebound. If you count 10 total clicks, youíre good to go. I found by tightening the top cap until it was snug (or bottomed out) on the damper rod, that was the correct position to get 10 clicks on rebound settings. However, if you have 9 or less clicks, you need to raise the top nut on the threaded damper rod. Check the number of clicks. If you have 11 or more clicks, you need to lower the top nut on the threaded damper rod. Check the number of clicks each time you raise, or lower the top cap on the damper rod to get it set at 10 clicks. No more, no less. Once itís correct, tighten the lock nut to 20Nm and set the rebound to the number you noted at the beginning of the project.

Release the spring compression tool and the internals should be tight against each other.

Continued:
Raise the upper fork tube and start threading it on the top cap.

Be careful not to pinch or kink the rubber O-ring when tightening the top cap down on the fork tube.

Now that the fork is all buttoned up, check it for smooth compression and rebound by holding the fork firmly on the floor and push down on the top tube as the bike would do under braking. If it feels good and does not bottom out on the brake caliper mounts, itís time to reinstall the fork on your bike. The torque setting for the triple tree bolts is 19Nm. Once the fork is installed in the triple tree, be sure to torque the top cap to 20Nm too!

Now itís time to repeat this procedure for the other fork!

Time wise for each fork, it took me about 45 minutes from removing the fork from the bike, draining the oil, disassembly, refilling, measuring, reassembly of internals, checking rebound settings and tightening the top cap back on the upper tube. Keep in mind, this was my first time, so experience will certainly reduce the time it takes to change the fluid next time.

Excellent write-up. What kind of riding are you doing (street or track) and how frequently do you plan to change the fork oil?

Mostly track riding in the A Group with NESBA about mid pack pace. I bought it used from California Superbike School a year ago with 17,500 miles and it now has about 21,000 miles on it. They never changed the fork oil, so it was certainly overdue. I did 14 trackdays this year at various tracks from VIR North and South, Summit Main, Road Atlanta and even did Barber a year ago a few weeks after I got the bike. VIR is my "home" track and I'm generally in the low 1:40s on the North with a few 1:39s and even a couple of 1:38's when I was chasing a rabbit. I plan on changing the oil every year since it's fairly easy and saves me quite a bit from having to take it to a shop. I'll be glad to answer any other questions too!

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